Technical Field
[0001] The present invention relates to an automatic analysis apparatus for clinical examination
and a sample measuring method.
Background Art
[0002] An absorptiometer to measure a transmitted light quantity is used for an automatic
analysis apparatus for clinical examination. There are two kinds of measurement principles,
namely a measurement principle using the following enzyme and a measurement principle
using antigen-antibody reaction, in the reaction principle of a sample and a reagent
in an examination item and two kinds of major reactions, namely color reaction between
a substrate and an enzyme and agglutination reaction between an antigen and an antibody,
are used for the reaction of a reaction liquid.
[0003] The former is biochemical analysis and LDH (lactate dehydrogenase), ALP (alkaline
phosphatase), and AST (aspartate oxoglutarate aminotransferase) are named as the examination
items.
[0004] The latter is immune assay and CRP (C-reactive protein), IgG (immunoglobulin), and
RF (rheumatoid factor) are named as the examination items.
[0005] The concentration of a substance in blood measured at the immune assay is low and
thus a high sensitivity is required. A high sensitivity has heretofore been tried
in a latex immunoagglutination method for quantitating the quantity of an ingredient
contained in a sample by: using a reagent produced by sensitizing (binding) an antibody
on the surface of a latex particle; projecting light to a reaction liquid when the
ingredient contained in the sample is recognized and agglutinated; and measuring the
quantity of the light that is not scattered by a latex aggregate and has been transmitted.
[0006] As a sample analysis apparatus to analyze the quantity of an ingredient contained
in a sample, an automatic analysis apparatus to irradiate a sample or a reaction liquid
produced by mixing a sample and a reagent with light from a light source, measure
the quantity of the transmitted light of a single wavelength or plural wavelengths
obtained resultantly and compute an absorbance, and determine an ingredient quantity
from the relationship between the absorbance and a concentration in accordance with
the Lambert-Beer law is widely used. In such an apparatus, a plurality of cells retaining
a reaction liquid are arranged circumferentially on a cell disk repeating rotation
and stop and the chronological change of an absorbance is measured at regular time
intervals for about 10 minutes with a prearranged transmitted light measuring unit
during the rotation of the cell disk.
[0007] In an automatic analysis apparatus for clinical examination, a method of measuring
the absorbance of a reaction liquid in a reaction container while it is rotated is
the mainstream. The method is called a turntable discrete method. In the method, measurement
is carried out once while a reaction disk on which a reaction container is set makes
one revolution. The absorbance of the reaction container is measured at regular cyclic
intervals.
[0008] In the turntable discrete method, reagent dispensing is carried out multiple times
(R1, R2, ····) in one cycle. As one cycle, there are several methods including a control
method of rotating a reaction disk at one revolution and a degree corresponding to
the reaction container and a control method of rotating a reaction disk at a fraction
of one revolution plus a degree corresponding to the number of the reaction containers.
The difference between the methods depends on the layout of a reagent dispensing mechanism
and the alignment of R1, R2 stirring mechanisms.
[0009] A feature of the method is to measure a reaction liquid in a reaction container at
regular intervals. Another feature thereof is to be able to monitor the reaction process
between a sample and a reagent during measurement.
[0010] In an automatic analysis apparatus for clinical examination, to increase sensitivity
not by measuring a transmitted light quantity with a photometer but by measuring a
scattered light quantity is also attempted. When a reagent making use of antigen-antibody
reaction is used, an antigen contained in a sample is reacted with an antibody contained
in the reagent. A reactant is produced by antigen-antibody reaction, the particle
is irradiated with light, and the magnitude of the scattered light or transmitted
light is measured. A light-scattering photometer, a so-called nephelometer, is used.
[0011] For example, a system of separating transmitted light from scattered light with a
diaphragm and measuring an absorbance and the scattered light simultaneously (Patent
Document 1), a configuration of increasing accuracy on the higher concentration side
by measuring the light reflected and scattered at a large aggregate formed as a result
of the advancement of agglutination reaction (Patent Document 2), and a method of
measuring the respective average light quantities of forward-scattered light and backscattered
light with an integrating sphere in front of and at the back of a reaction container
and correcting the turbidity change caused by the misregistration of a cell (Patent
Document 3) are disclosed.
Prior Art Documents
Patent Document
Summary of the Invention
Problem to be solved by the Invention
[0013] As stated above, a method of mounting a light-scattering photometer and an absorptiometer
on an apparatus and combining the light-scattering photometer and the like with the
absorptiometer is described in Patent Documents 1 and 2.
[0014] Since sensitivity cannot be compared simply between a light-scattering photometer
and an absorptiometer mounted on an apparatus however, a method of judging a concentration
range and an optical system to be used that make highly accurate measurement possible
has been unknown. Consequently, an automatic analysis apparatus having both a light-scattering
photometer and an absorptiometer has been useless as an actual apparatus.
[0015] In a reagent based on the measurement principle of immune nephelometry or latex nephelometry,
the type and characteristics of an antibody contained in the reagent, the normal value
range of a measurement item, a lowest detection sensitivity, turbidity by the influence
of bilirubin contained in a sample, hemolysis, and high fat, and others determine
the performance of a measuring object.
[0016] In an instrument, an absorptiometer using a conventional automatic analysis apparatus
and a light-scattering photometer for improving reagent sensitivity are used. Problems
on the influential factors, an absorptiometer, and a light-scattering photometer are
described below.
(1) Relationship between absorptiometer and reagent
[0017] In an absorptiometer, a halogen lamp is used as the light source and measurement
is carried out simultaneously in a plurality of wavelength regions ranging from ultraviolet
to near-infrared. Measurement can be carried out while a wavelength region susceptible
to the influence of hemolysis, bilirubin, and the like is avoided. The wavelength
can be selected in conformity with the particle size of latex and a measurement range
and linearity is also kept wide. Since light of a wide range is projected however,
the measurement sensitivity at a low concentration is inferior. In the vicinity of
O in particular, it is impossible to know the difference because of transmitted light.
(2) Relationship between light-scattering photometer and reagent
[0018] Since light of a single wavelength is projected and scattered light is measured,
sensitivity at a low concentration is good. In a sample of a high concentration, the
diameter of an antigen-antibody product increases, multiple scattering is caused,
and the measurable range is narrow. Since light of a single wavelength is projected,
the diameter of a latex particle that can be appropriately measured is limited. In
order to appropriately measure latex particles ranging from small diameters to large
diameters however, it is necessary to prepare a plurality of light-scattering photometers
having different irradiation wavelengths.
[0019] As stated above, there are several discrepancies in the combination of a method using
antigen-antibody reaction, a reagent and an instrument, and an absorptiometer and
a light-scattering photometer.
[0020] With regard to the measurement of an immune item, particularly of a latex reagent,
the case of consolidating plural analyzers including a light-scattering photometer
and the like in addition to a heretofore existing absorptiometer into an automatic
analysis apparatus is examined as follows.
[0021] Since plural photometers are used in combination, data processing and the setting
of analysis parameters for at least two kinds of optical systems (at least two kinds
of independent analysis parameters) are required.
[0022] In an analysis apparatus having a single optical system of prior art, with regard
to each of analysis items: parameters such as a sample quantity, a reagent quantity,
a wavelength, a reaction time, and others are decided in accordance with an analysis
method for reaction; the dispensing of a reagent and the analysis of measurement are
carried out in accordance with the decided basic parameters; and a concentration is
computed.
[0023] The calibration of a reagent is required prior to general patient sample analysis.
In general, whether a reagent is good or bad is judged from the reaction result by
using the sensitivity of the reagent and the standard solution and the variation of
the sensitivity and an absorbance of the reagent. In a conventional automatic analysis
apparatus, S1ABS, SENS, DUP, and so on are checked.
[0024] In another photometer such as a light-scattering photometer too, the calibration
of a reagent is carried out and whether the reagent is good or not is judged. The
judgment values are carried out as judgment against the measurement conditions of
a relevant analysis parameter. As a method for judgment, there is a method of deciding
an allowable value of each reagent lot at a reagent maker. Further as another judgment
method, there is the case of judging occasionally from a calibration result.
[0025] A light-scattering photometer and an absorptiometer have fundamental features respectively.
The performance comparison table of a light-scattering photometer and an absorptiometer
is shown in Table 1.
[0026] [Table 1]
Table 1: Performance comparison between light-scattering photometer and absorptiometer
|
Absorptiometric method |
Scattered light |
Transmitted light |
High resolution |
○ |
⊙ |
○ |
Linearity |
⊙ |
Δ |
⊙ |
Influence of coexisting material |
|
|
|
Hemolysis |
⊙ |
○ |
|
Bilirubin |
⊙ |
○ |
|
RF |
○ |
○ |
|
Turbidity |
○ |
⊙ |
|
[0027] As shown in Table 1, the performance including resolution, linearity, the influence
of a coexisting material, and so on is not entirely satisfied with only one type photometer.
[0028] In this way, since the full performance is not satisfied with only one type photometer,
analysis is carried out by the combination of: an apparatus dedicated to immune nephelometry,
which is operated with plural apparatuses having different analytical principles (light-scattering
photometer); and an automatic analysis apparatus for biochemistry on which a conventional
absorptiometer is mounted.
[0029] Even when an apparatus of a high sensitivity is prepared therefore, it is necessary
to: change the dilution of a sample and the quantity of the sample so that a low concentration
and a high concentration may be obtained for each measurement item and for each patient
sample as reexamination after once the patient sample is measured; and switch between
measurement with a light-scattering photometer and measurement with an absorptiometer.
Consequently, workflow becomes complex and the possibility of operator's mistake increases.
Further, a long examination time is required.
[0030] With one type of optical systems, the sensitivities can be compared by the outputs
of the optical systems. With optical systems of different principles however, the
sensitivities of the optical systems of different principles cannot be simply compared
with each other. In prior art therefore, in the case of mounting two types of photometers
of a light-scattering photometer and an absorptiometer on an automatic analysis apparatus,
the detection sensitivity has been hardly improved because the respective detection
sensitivities have been hardly compared and an optimum photometer has been decided
in accordance with a concentration range.
[0031] An object of the present invention is to materialize an automatic analysis apparatus
and a sample measuring method, which are capable of: deciding an optimum photometer
from the two photometers of a light-scattering photometer and an absorptiometer in
accordance with a concentration range; and improving detection sensitivity.
Means for solving the Problems
[0032] In order to attain the object, the present invention is configured as follows.
[0033] In an automatic analysis apparatus and a sample measuring method: the operations
of a sample dispensing mechanism to intake and discharge a sample to a reaction container
and a reagent dispensing mechanism to intake and discharge a reagent to the reaction
container are controlled; the allowable concentration range of a calibration curve
is set for each of a plurality of photometers to detect the light projected to the
reaction container; one of the plural photometers is selected in accordance with the
concentration of the sample computed on the basis of the light detected with each
of the plural photometers in the set allowable concentration range; and the concentration
based on the light detected with the selected photometer is decided as the concentration
of the sample.
Effects of Invention
[0034] The present invention makes it possible to materialize an automatic analysis apparatus
and a sample measuring method, which are capable of: deciding an optimum photometer
from the two photometers of a light-scattering photometer and an absorptiometer in
accordance with a concentration range; and improving detection sensitivity.
Brief Description of Drawings
[0035]
Fig. 1 is a schematic general configuration diagram of an automatic analysis apparatus
to which an example according to the present invention is applied.
Fig. 2 is a view explaining the arrangement of a light source, a reaction container,
and a light-scattering photometer 15 in an example according to the present invention.
Fig. 3 is a schematic top view of a reaction disk in an example according to the present
invention.
Fig. 4 is a view showing the database configuration of parameters in each of the items
in an example according to the present invention.
Fig. 5 is a view showing the relationship of reaction among transmitted light, scattered
light, and an absorbance.
Fig. 6 is a graph showing the relationship among an absorbance, a scattering intensity,
and a concentration in an RF.
Fig. 7 is a graph showing the relationship among an absorbance, a scattering intensity,
and a concentration in an RF.
Fig. 8 is a view showing the flow of judging a concentration from a sensitivity or
a concentration range and selecting a photometer in an example according to the present
invention.
Fig. 9 is a graph showing the relationship between a scattered light intensity or
an absorbance and a concentration.
Fig. 10A is a graph showing an example of setting the allowable range of a calibration
result from the double-width of Max/Min of the twice measurement result of each standard
solution in an example according to the present invention.
Fig. 10B is a graph showing an example of setting the allowable range of a calibration
result from the double-width of Max/Min of the twice measurement result of each standard
solution in an example according to the present invention.
Fig. 11 is a view showing an example of setting the allowable range of calibration
from uncertainty attached to a standard solution in an example according to the present
invention.
Fig. 12 is a screen configuration diagram of an operation section in an example according
to the present invention.
Fig. 13 is a screen configuration diagram of an operation section in an example according
to the present invention.
Fig. 14 is a screen configuration diagram of an operation section in an example according
to the present invention.
Fig. 15 is an example of a screen of an operation section in an example according
to the present invention.
Fig. 16 is an example of a screen of an operation section in an example according
to the present invention.
Fig. 17 is an example of a screen of an operation section in an example according
to the present invention.
Fig. 18 is a functional block diagram of a computer (controller) in an example according
to the present invention.
Mode for Carrying out the Invention
[0036] Embodiments according to the present invention are explained hereunder in reference
to the attached drawings.
Embodiment 1
[0037] Prior to explanations on examples according to the present invention, immune reaction
and antigen-antibody reaction are explained.
[0038] In antigen-antibody binding reaction, the reaction to an antigen advances relatively
slowly. It is possible to monitor a reaction process by measuring an absorbance and
scattered light at intervals of several seconds since the reaction time is a level
of several minutes.
[0039] An absorptiometer measures an absorbance on the basis of the relative relationship
of the quantity of the light having penetrated a solution to irradiated light, namely
the Lambert-Beer Law, as shown in the following expression (1).
[0040] [Num-1]

[0041] A light-scattering photometer is based on the fact that scattered light does not
exist and nearly "zero" in the case of using water as a reaction solution and the
scattered light increases as an antigen-antibody reactant increases.
[0042] In general, a scattered light quantity of particles is described by the following
expression (2) when the scattering is regard mostly as Rayleigh scattering.
[0043] [Num-2]

[0044] Here, n represents the number of particles per 1 cm
3, V represents a total scattering volume, α represents a polarizability of particles,
and λ represents a wavelength.
[0045] Fig. 5 is a view showing the relationship of reaction among transmitted light, scattered
light, and an absorbance, and the vertical axis represents a light intensity and the
horizontal axis represents time. As shown in Fig. 5, the transmitted light (quadrangles)
reduces in proportion to the progress of reaction and the scattered light (triangles)
increases in proportion to the progress of reaction. Further, the absorbance (circles)
increases in proportion to the progress of reaction.
[0046] In the region of clinical examination, the detection limit and the quantification
limit of a measuring method have important implications from a clinical viewpoint
in the measurement of the concentration of a tumor marker or the like. The detection
limit: means the smallest detectable quantity of a measurement object substance existing
in a sample; and is not necessarily a quantifiable limit. The detection limit is obtained
by a method of: repeatedly measuring a blind sample and actual samples of known low
concentrations (5 or more kinds of dilution series) ; and reading the measured value
of the sample in which for example the average value of the blind sample + 3SD and
the average value of the low concentration sample - 3SD do not overlap with each other.
That is, the detection limit is obtained by measuring a sample the concentration of
which is known and measuring a signal quantity (sensitivity) with a photometer.
[0047] In contrast, the method of computing the concentration of a general patient sample
is a method of firstly measuring standard solutions of known concentrations at plural
points, thus making a calibration curve, successively measuring the sample, and obtaining
a concentration corresponding to a signal quantity from the calibration curve on the
basis of the signal quantity detected with a photometer.
[0048] In immunoserological test, an antigen contained in blood serum or blood plasma is
reacted with a reagent containing an antibody corresponding to the antigen and an
antigen-antibody product is produced. A concentration is computed from the absorbance
change or the scattered light change of the antigen-antibody product.
[0049] As measuring methods, there are a measuring method of using transmitted light and
a measuring method of using scattered light. By the scattered light measurement, it
is possible to detect a minute change of antigen-antibody reaction. As a result, the
detection limit at a lower concentration improves.
[0050] In the case of a sample having a high antigen concentration in contrast, the quantity
of an antigen-antibody product is large, scattered light increases scarcely in a high
concentration region, and the range of a straight line is narrow.
[0051] In immunoserological test, the influence by immunity, bilirubin, turbidity by lipid,
hemolysis caused by the fragmentation of erythrocytes, and others which are contained
in a sample of a patient is included.
[0052] The present invention is created on the basis of the above matters.
[0053] Example 1 according to the present invention is explained hereunder.
[0054] In Example 1 according to the present invention, a plurality of photometers (a light-scattering
photometer and an absorptiometer) are arranged along the circumference of a reaction
disk. That is, an immune nephelometer (light-scattering photometer) and an absorptiometer,
those being operated with the plural devices of different analysis principles, are
mounted on an automatic analysis apparatus for biochemistry.
[0055] Fig. 1 is a schematic general configuration diagram of an automatic analysis apparatus
to which Example 1 according to the present invention is applied. In Fig. 1, many
reaction containers 2 comprising a translucent material are mounted on and along the
circumference of a reaction disk 1 intermittently rotatably installed. The reaction
containers 2 are maintained at a given temperature (37 degrees C for example) by a
constant-temperature bath 3. The temperature of a fluid in the constant-temperature
bath 3 is controlled by a constant-temperature retainer 4.
[0056] Many sample containers 6 containing biological samples such as blood or urine are
arranged over a sample disk 5. A pipet nozzle 8 attached to a movable arm 7 intakes
a given quantity of a sample from a sample container 6 allocated at the intake position
of the sample disk 5 and discharges the sample in a reaction container 2 located at
the discharge position over the reaction disk 1.
[0057] A plurality of reagent bottles 10A and 10B to which labels showing reagent identification
information such as barcodes are attached are arranged over reagent disks 26A and
26B arranged in reagent cool boxes 9A and 9B, respectively. Reagent liquids corresponding
to analysis items that can be analyzed by the automatic analysis apparatus are contained
in the reagent bottles 10A and 10B.
[0058] Barcode readers 34A and 34B pertaining to the respective reagent cool boxes 9A and
9B read the barcodes displayed on the outer walls of the reagent bottles 10A and 10B
when reagents are registered. The read reagent information is registered in a memory
11 that will be described later, together with the information on the positions over
the reagent disks 26A and 26B.
[0059] Reagent pipet nozzles in respective reagent dispensing mechanisms 12A and 12B: intake
reagent liquids from the reagent bottles 10A and 10B corresponding to the examination
items allocated at reagent receiving positions over the reaction disk 1; and discharge
the reagent liquids to the relevant reaction containers 2. The mixtures of the samples
and the reagents contained in the reaction containers 2 are stirred with stirring
mechanisms 13A and 13B. The array of the reaction containers 2 moves rotatably so
as to pass through photometric positions interposed between light sources 14 (light
sources 14A and 14B) and photometers 15 (a light-scattering photometer 15A and a multi-wavelength
absorptiometer 15B). The photometers 15 can compute concentrations by using both scattered
light and transmitted light. Here, the placement of the detectors in the photometers
15 is described later in reference to Figs. 2 and 3.
[0060] The reaction liquid of the sample and the reagent in each of the reaction containers
2 is photometrically measured during the rotary operation of the reaction disk 1 every
time when the reaction liquid intersects the front of the photometers 15. Each of
the samples is measured with the photometers 15 and the outputted analog signals are
inputted in an A/D converter 16. A reaction container cleaning mechanism 17 arranged
in the vicinity of the reaction disk 1 makes it possible to use the reaction containers
2 repeatedly by cleaning the interior of a used reaction container 2.
[0061] Successively, a control system and a signal processing system in an automatic analysis
apparatus shown in Fig. 1 are explained briefly.
[0062] A computer 18 is connected to a sample dispensing control section 20, a reagent dispensing
control section 21, and the A/D converter 16 through an interface 19. The computer
18 sends a command to the sample dispensing control section 20 and controls the dispensing
operation of a sample. Further, the computer 18 sends a command to the reagent dispensing
control section 21 and controls the dispensing operation of a reagent.
[0063] The analog signals outputted from the photometers 15 are converted to digital signals
with the A/D converter 16 and taken in the computer 18.
[0064] A printer 22 for printing, a memory 11 and an external output medium 23 as storage
devices, a keyboard 24 for inputting operation commands and the like, and a CRT display
25 for displaying a screen are connected to the interface 19. As a screen display
device, in addition to a CRT display, a liquid crystal display or the like can be
adopted. The memory 11 comprises a hard disk memory or an external memory for example.
In the memory 11, information on the password of each operator, the display level
of each screen, analysis parameters, the requested contents of analysis items, calibration
results, analysis results, etc. is stored.
[0065] Successively, the analytical operations of a sample in the automatic analysis apparatus
shown in Fig. 1 are explained. Analysis parameters related to items analyzable with
the automatic analysis apparatus are inputted through an information input device
like the keyboard 24 beforehand and stored in the memory 11. An operator selects examination
items required of each sample by using an operational function screen that will be
described later.
[0066] On this occasion, information such as a patient ID is also inputted from the keyboard
24. In order to analyze an examination item indicated to each sample, the pipet nozzle
8 dispenses a given quantity of a sample from a sample container 6 to a reaction container
2 in accordance with an analysis parameter.
[0067] The reaction container 2 having received the sample is transferred by the rotation
of the reaction disk 1 and stops at a reagent receiving position. A pipet nozzle of
a reagent dispensing mechanism 12A or 12B dispenses a given quantity of a reagent
liquid to the reaction container 2 in accordance with the analysis parameter of the
relevant examination item. With regard to the sequence of dispensing a sample and
a reagent, inversely to the above case, a reagent may be dispensed in advance of a
sample.
[0068] Successively, the sample and the reagent are stirred and mixed with a stirring mechanism
13A or 13B. When the sample and the reagent are stirred and the reaction container
2 intersects a photometric position, the scattered light or the absorbance of the
reaction liquid is photometrically measured with the photometers 15. The photometrically
measured scattered light or the like is converted to a numerical value proportional
to a light quantity or the like with the A/D converter 16 and taken into the computer
18 through the interface 19. The converted numerical value is converted to a concentration
datum on the basis of a calibration curve measured beforehand by an analysis method
designated to each examination item. An ingredient concentration datum as an analysis
result of each examination item is outputted to the printer 22 or on the screen of
the CRT 25.
[0069] In advance of the implementation of the measurement operations, an operator carries
out the setting of various parameters and the registration of a sample required for
analytical measurement through the operation screen of the CRT 25. Further, the operator
checks the analysis result after the measurement on the operation screen of the CRT
25.
[0070] Successively, the arrangement of a light source 14 and a photometer 15 shown in Fig.
1 is explained in reference to Figs. 2 and 3.
[0071] Fig. 2 is a view explaining the arrangement of a light source 14, a reaction container
2, and a light-scattering photometer 15A (detectors 203, 204, and 205).
[0072] The light emitted from the light source 14 is projected to the reaction container
2 in which a measurement object is dispensed. The incident light collides with the
measurement object and is scattered in the reaction container 2. With regard to the
scattered light, in the case of Fig. 2, the detector 203 is arranged at a position
forming an angle of θ1 with the light coming from the light source 14 and having passed
through the reaction container 2 in the vertical direction (Z-axis direction) of the
apparatus. Further, the detector 204 is arranged in the direction (angle zero) of
the light coming from the light source 14 and having passed through the reaction container
2. Furthermore, the detector 205 is arranged at a position forming an angle of θ2
with the light coming from the light source 14 and having passed through the reaction
container 2 in the vertical direction (Z-axis direction) of the apparatus.
[0073] Although the detectors 203, 204, and 205 are allocated in the Z-axis direction to
the incident light, it is also possible to be allocated by changing the angles to
the horizontal direction (X-axis and Y-axis directions) of the apparatus. Further,
the detectors 203, 204, and 205 are not necessarily allocated discretely but may be
allocated continuously.
[0074] Fig. 3 is a schematic top view of the reaction disk 1 and shows arrangement positions
of the light-scattering photometer 15A and the absorptiometer 15B. In the automatic
analysis apparatus configured as shown in Fig. 1, the light-scattering photometer
15A and the absorptiometer 15B are aligned on the lines where the light from the light
sources 14A and 14B passes through a reaction container 2.
[0075] Each analysis item of a sample is measured simultaneously with the light-scattering
photometer 15A and the absorptiometer 15B and the reaction process is made measurable.
It is important that the light-scattering photometer 15A and the absorptiometer 15B
can measure nearly simultaneously. The setting contents of analysis parameters, concentration
computation, and data abnormality detection by an interference substance in a sample
in the light-scattering photometer 15A and the absorptiometer 15B are explained hereunder.
[0076] A reagent quantity and a sample quantity in the analysis parameters are used commonly
by the light-scattering photometer 15A and the absorptiometer 15B and, with regard
to other items including wavelength selection, a measurement point, alarm setting,
and a calibration condition, the parameters are used independently between the photometers
15A and 15B.
[0077] The procedure of the calibration, concentration, data check, and alarm generation
of the absorptiometer 15B and the light-scattering photometer 15A is described. The
data flow is represented by the following procedure. The procedure is (1) parameter
setting, (2) calibration parameter computation, (3) concentration computation, (4)
concentration judgment logic, and (5) interference substance check and they are explained
in sequence.
(1) Parameter setting
[0078] The measurement parameters of a plurality of optical systems are made settable for
each item. Table 2 is a list of the parameters.
[0079] [Table 2]
Table 2: Parameter list
|
Absorptiometer |
Light-scattering photometer |
Common parameter |
|
|
Item name |
AFP |
|
Type |
Serum |
|
Sample quantity |
1.0-30.0µL |
|
Reagent quantity |
10-150µL |
|
(R1) |
10-150µL |
|
Reagent quantity |
10-150µL |
|
(R2) |
|
|
Reagent quantity |
|
|
(R3) |
|
|
Individual parameter |
|
|
Wavelength |
340-800 nm |
Angle selection |
|
selection |
0°/±20° /±30° |
|
|
To retain data for each angle |
Photometric point |
19-34 points |
19-34 points |
Analysis method |
End point/2 points/rate selection |
End point/2 points/rate selection |
Calibration method |
Linear/NonLinear |
Linear/Non- Linear |
Calibration point number |
6 points |
6 points |
Mutual parameter |
|
Linearity (concentration range) |
Range setting of concentrations low/middle/high |
Linearity (Concentration conversion) |
To select absorptiometer/light-scattering photometer according low/middle/high to
concentrations |
Coexisting material |
To designate check low/middle/high value according to concentrations |
L (Turbidity) |
To designate check low/middle/high value according to concentrations |
H (Hemolysis) |
To designate check low/middle/high value according to concentrations |
I (Yellow) |
|
Alarm check |
|
|
Convergence |
Range |
Range designation |
allowable absorbance/scattered light intensity |
designation |
|
|
Range designation |
Variation allowable absorbance/scattered light intensity |
Range designation |
|
|
Range designation |
Sensitivity allowable absorbance/scattered light intensity |
Range |
|
designation |
Range designation |
First standard solution absorbance/scattered light intensity range |
Range designation |
Range designation |
Range designation |
|
Range designation |
Linearity check |
Range |
|
Prozone limit value |
designation |
|
Reaction limit absorbance/scattered light intensity |
Range designation |
|
Range designation |
|
[0080] Common parameters (a sample quantity and a reagent quantity) ranging over the plural
optical systems, intrinsic parameters specific to the respective photometers 15A and
15B, mutual parameters of a concentration from data related to the plural photometers
15A and 15B, and parameters for alarm check, those being shown in Table 2, are stored
in a database.
[0081] Fig. 4 is a view showing the database configuration of common parameters, parameters
dedicated to an absorptiometer, parameters dedicated to a light-scattering photometer,
concentration computation parameters, and coexisting material check parameters for
each item.
(a) Common parameters
[0082] Parameters, such as a sample quantity, a dispensing reagent quantity, and a normal
value range, related to quantity are set.
(b) Parameters dedicated to absorptiometer
[0083] Parameters, such as a wave length (dominant wavelength/complementary wavelength),
an analysis method (1 point, 2 points, Rate), a photometric point, and calibration
(number and concentration), used for computation in an absorptiometric method are
set.
(c) Parameters dedicated to light-scattering photometer
[0084] An angle is selected from among 0 degree, ±10 degrees, ±20 degrees, and ±30 degrees
for example. The parameters are the parameters, such as an analysis method (1 point,
2 points, Rate), a photometric point, and calibration (number and concentration),
used for computation in a light-scattering photometric method and are set for each
scattering angle.
(d) Concentration computation parameters
[0085] The parameters are the parameters related to interrelationship between absorbance
measurement and light-scattering photometer measurement and the parameters of linearity
and coexisting material check are set.
[0086] When sensitivity is compared between a plurality of optical systems, between a light-scattering
photometer 15A and an absorptiometer 15B for example, the signals are different and
hence a sensitivity per unit concentration cannot simply be compared. In the optical
measurement of latex particles or the like, the scattering of light is measured in
the blank state of a latex particle solution even in an unreacted state. Further,
with the absorptiometer 15B, scattering occurs and hence a large absorbance value
is measured. When a blank solution of latex is measured with the light-scattering
photometer 15A, the scattered light reduces comparatively.
[0087] The relationship of latex particles is described by the following items (1-1) to
(1-4).
(1-1) A measurement result varies in accordance with the conditions of a latex particle
diameter, the number of particles per unit volume, and an irradiation wavelength.
(1-2) The magnitude of scattered light is largely different between a latex single
body and a latex body formed after an antibody has reacted with an antigen on the
surface of the latex.
(1-3) In general, also the affinity between an antibody and an antigen has a large
influence.
(1-4) The relationship of sensitivity between scattered light and an absorbance in
the case where the concentration of an antigen is high is largely different from the
case of a low concentration.
[0088] Successively, linearity and coexisting material check parameters are explained.
(I) Linearity (allowable range setting in each calibration)
[0089] A concentration range, for example, may be divided into three levels of low concentration,
middle concentration, and high concentration from a curve of calibration with an absorptiometer
15B or may be divided in accordance with the concentrations of each standard solution.
[0090] In order to set a concentration computation method used in each concentration range,
it is necessary to decide a signal (photometer) used in each region from calibration
result. In deciding the parameter of linearity, the following three items (a), (b),
and (c) are retained.
- (a) To input a concentration range decided from a relevant reagent lot by experiment
or the like beforehand.
- (b) To decide a concentration range usable in each optical system from the measurement
result of a plurality of optical systems, the sensitivity of a reagent, and the like
and set the range automatically.
- (c) An allowable range can be inputted arbitrarily by an operator. It can be set manually.
[0091] In the item (a), for example a reagent maker decides a concentration range for each
reagent lot and provides the information to a user. In the item (b), the sensitivity
of the light-scattering photometer 15A is obtained in terms of a light quantity change
ratio in order to compare the sensitivity between the light-scattering photometer
15A and the absorptiometer 15B. The light quantity change ratio is a value obtained
by subtracting a base light quantity immediately after a second reagent is added from
the variation of a light quantity changed between before and after reaction and the
scattering of light in a blank state can be disregarded.
[0092] The sensitivities of the light-scattering photometer 15A and the absorptiometer 15B
ranging from a low concentration to a high concentration are different largely also
in accordance with a reagent lot and an analysis item. It comes to be important for
a system comprising a plurality of photometers to carry out measurement with an optimum
optical system in each of the concentration regions ranging from a low concentration
to a high concentration.
[0093] The workflow (b) to judge an optimum photometer from a photometer A and a photometer
B is explained hereunder on the basis of a certain standard value.
[0094] Here, the standard sensitivity A of the photometer A is set at 0.001 and the standard
sensitivity B of the photometer B is set at 0.002. When calibration is carried out
with a certain reagent lot, the calibration result A is 0.002 and the calibration
result B is 0.005. If the calibration results are compared with the standard sensitivities,
the sensitivity of the photometer A increases by 2 times, the sensitivity of the photometer
B increases by 2.5 times, and on this occasion the photometer B of a higher sensitivity
is selected.
(II) Coexisting material check parameters
[0095] When data dissociation occurs between an absorptiometer 15B and a light-scattering
photometer 15A, a value for judging that the data dissociate between the absorptiometer
15B and the light-scattering photometer 15A is set.
[0096] Screen configuration diagrams of an operation section in the aforementioned parameter
setting are shown in Figs. 12 to 14 and screen examples of the operation section are
shown in Figs. 15 to 17.
[0097] That is, as shown in Figs. 12 to 14, in application setting, there are three items
of analysis, calibration, and a standard solution, and Fig. 12 shows the setting items
of analysis, Fig. 13 shows the setting items of calibration, and Fig. 14 shows the
setting items of a standard solution.
[0098] As shown in Fig. 12, in the analysis, there are common items, items on a light-scattering
photometer, and items on an absorptiometer and, in the common items, there are an
item name, a diluent, an analysis method, a sample quantity, a dispensing reagent
quantity, a dummy reagent quantity, and a cell detergent. Further, in the items on
a light-scattering photometer, there are a photometric point, a scattered light receiving
angle, a reaction limit scattered light intensity, a prozone limit value, and scattered
light intensity difference check. Furthermore, in the items on an absorptiometer,
there are a photometric point, a wavelength, a reaction limit scattered light intensity,
a prozone limit value, and scattered light intensity difference check.
[0099] Fig. 15 is a view showing an example of a setting screen 25A on analysis. Analysis
is selected from the three items of analysis, calibration, and a standard solution.
In the example of Fig. 15, IRI is selected as the item name and selections on a sample
quantity, a dispensing reagent quantity, a dummy reagent quantity, and a cell detergent,
selections on an analysis method, a photometric point, and a wavelength of an absorptiometer,
and selections on an analysis method, a photometric point, and a light receiving angle
of a light-scattering photometer are carried out.
[0100] Further, as shown in Fig. 13, in calibration, there are common items, items on a
light-scattering photometer, and items on an absorptiometer and, in the common items,
there are an item name and a concentration computation method. Further, in the items
of a light-scattering photometer, there are a calibration method, a point, a convergence
allowable scattered light intensity, a variation allowable scattered light intensity,
a sensitivity allowable scattered light intensity, and a first standard solution scattered
light intensity range. Furthermore, in the items on an absorptiometer, there are a
calibration method, a point, a convergence allowable absorbance, a variation allowable
absorbance, a sensitivity allowable absorbance, and a first standard solution absorbance
range.
[0101] Fig. 16 is a view showing an example of a setting screen 25B on calibration. Calibration
is selected from the three items of analysis, calibration, and a standard solution.
In the example of Fig. 16, IRI is selected as the item name and automation is selected
as a concentration computation method. Then selections on a calibration method, a
point, a convergence allowable absorbance, a variation allowable absorbance, a sensitivity
allowable absorbance, and a first standard solution absorbance range of an absorptiometer
are carried out and further selections on a calibration method, a point, a convergence
allowable scattered light intensity, a variation allowable scattered light intensity,
a sensitivity allowable scattered light intensity, and a first standard solution scattered
light intensity range of a light-scattering photometer are carried out.
[0102] Further, as shown in Fig. 14, in a standard solution, there are a common item, items
on a light-scattering photometer, and items on an absorptiometer and, in the common
item, there is an item name and, in the items on the light-scattering photometer and
the absorptiometer, there are a calibrator code, a concentration, a position, and
a sample quantity, respectively.
[0103] Fig. 17 is a view showing an example of a setting screen 25C on a standard solution.
A standard solution is selected from the three items of analysis, calibration, and
the standard solution. In the example of Fig. 17, IRI is selected as the item name
and selections on a calibrator code, a standard solution concentration, a position,
and a sample quantity are carried out in each of an absorptiometer and a light-scattering
photometer.
(2) Calibration parameter computation
[0104] The measurement of a blank solution and a standard solution is carried out and calibration
parameters are computed. Calibration parameters of both the absorptiometric method
and the light-scattering photometer are computed. When computations are carried out
at scattering angles of 20 and 30 degrees and by the absorptiometric method, three
kinds of K factors are obtained through the expressions (3) to (5).
[0105] In the absorptiometric method, when a blank is represented by S1Abs, a blank concentration
by Conc.B, an absorbance of a standard solution by Abs
s, and a standard solution concentration by Conc.S, a factor K is computed through
the following expression (3).
[0106] [Num-3]

[0107] At a scattering angle of 20 degrees in the light-scattering photometer, when a blank
is represented by I
B20, a blank concentration by Conc.B, a standard solution by I
s20, and a standard solution concentration by Conc.S, a factor K
20 is computed through the following expression (4).
[0108] [Num-4]

[0109] At a scattering angle of 30 degrees in the light-scattering photometer, when a blank
is represented by I
B30, a blank concentration by Conc.B, a standard solution by I
s30, and a standard solution concentration by Conc.S, a factor K
30 is computed through the following expression (5).
[0110] [Num-5]

[0111] The calibration parameters are stored in a database such as a memory 11.
[0112] When calibration is carried out with an approximate curve by using a multipoint calibration
curve and a plurality of standard solutions, in the absorptiometric method, A, B,
and C parameters are stored in addition to S1ABS and K. In the light-scattering photometer,
A, B, and C parameters are stored in addition to I
B and K.
(3) Measurement and concentration computation of general sample
[0113] A calibration curve is created individually for each of the optical systems of the
absorptiometric method and the light-scattering photometer.
[0114] Concentration conversion for a patient sample is carried out with a plurality of
calibration curves. The concentration conversion formulae are shown hereunder. Concentrations
are computed for both the cases of the absorbance and the light-scattering photometer.
When the concentrations are computed at the scattering angles of 20 and 30 degrees
and with the absorptiometer, three kinds of concentrations are obtained through the
expressions (6) to (8).
[0115] In the case of the absorptiometer, a concentration Conc
Abs is obtained through the following expression (6).
[0116] [Num-6]

[0117] In the case of the light-scattering photometer, concentrations Conc
20N and Conc
30N are obtained through the following expressions (7) and (8).
[0118] [Num-7]

[0119] [Num-8]

[0120] Table 3 shows the measurement results of an RF in the cases of computing the concentrations
at the scattering angles of 20 and 30 degrees and with the absorptiometer.
[0121] [Table 3]
Table 3: RF measurement result when concentrations are computed with light-scattering
photometer and absorptiometer
Concentration region IU/mL |
Absorbance Conc.Abs |
Light-scattering photometer |
Conc.20N |
Conc.30N |
Low concentration |
1.7 |
0.3 |
0.3 |
Middle concentration (normal region) |
8.8 |
10.0 |
10.0 |
High concentration |
310.0 |
173.4 |
116.5 |
(4) Concentration judgment logic
[0122] Figs. 6 and 7 are the graphs showing the relationships between an absorbance/a scattering
intensity and a concentration in an RF. As shown in Fig. 7, in the light-scattering
photometer, the signal reduces at a high concentration. Consequently, even in the
case of a sample originally having a high concentration, the concentration is equivalent
to an absorbance of a middle concentration and may possibly be displayed as a low
concentration.
[0123] In contrast, as shown in Fig. 6, in the case of the absorptiometer, even at a high
concentration, the absorbance does not reduce and is higher than that of a middle
concentration.
[0124] In the low concentration region, the sensitivity of the light-scattering photometer
is better than that of the absorptiometer. In the case of the light-scattering photometer,
a prozone phenomenon is caused at the high concentration region. It sometimes happens
that a scattered light intensity comes to be equivalent to a scattering intensity
of a lower concentration in despite of a high concentration.
[0125] Fig. 8 is a view showing the flow of judging a concentration from a sensitivity or
a concentration range and selecting a photometer. Further, Fig. 18 is a functional
block diagram of a computer (controller) 18 and is a view related to the function
of carrying out the flow shown in Fig. 8.
[0126] In Fig. 18, the computer (controller) 18 comprises: an operation control section
18a to control the operations of a reaction disk 1, photometers 15, and others; a
calibration curve creating section 18b; an application concentration range setting
section 18c; a sensitivity computation section 18d; and a photometer selection section
18e.
[0127] A concentration judgment flow shown in Fig. 8 to select a photometer by comparing
sensitivities is explained in reference to Figs. 8 and 18. The concentration judgment
and photometer selection flow shown in Fig. 8 is carried out by the computer 18 controlling
the operations of the sections and mechanisms of an automatic analysis apparatus on
the basis of the parameters and the like stored in the memory 11.
[0128] In Fig. 8, in order to compare optical system sensitivities of different principles,
the width of a concentration is computed from a calibration result. The procedure
is as follows.
(4-1) The operation control section 18a and the calibration curve creating section
18b measure a standard solution multiple times by ordinary calibration and create
a calibration curve (Step S1).
(4-2) The calibration curve creating section 18b creates the respective calibration
curves of the absorptiometer and the light-scattering photometer from the measurement
values of Min/Max of the concentrations of the respective standard solutions (Step
S2).
(4-3) The application concentration range setting section 18c computes the upper/lower
limits of the standard solution concentrations from the calibration curves of Min/Max
(Step S3).
(4-4) The sensitivity computation section 18d computes sensitivities (signal quantities)
from the data of the absorptiometer 15B and the light-scattering photometer 15A by
using calibration parameters (Steps S3 and S4).
(4-5) The photometer computation section 18e decides the concentration to be used
from a concentration by absorption and a concentration by scattered light on the basis
of the sensitivities computed by the sensitivity computation section 18d (Step S5).
That is, the computed sensitivities of the concentration by absorption and the concentration
by scattered light are compared and the use of the concentration having a higher sensitivity
is decided. The decided concentration is displayed on the CRT 25 (a concentration
display section).
[0129] By the workflow shown in Fig. 8, it is possible to estimate a sensitivity from the
maximum and the minimum obtained when the standard solution is measured multiple times
and convert it to a concentration on the basis of the result. That is, the sensitivities
of the respective optical systems (the absorptiometer and the light-scattering photometer)
are computed as concentrations from the calibration results and hence the comparison
between the sensitivity of the absorptiometer and the sensitivity of the light-scattering
photometer can be facilitated.
[0130] The concentration range applied in the concentration judgment flow shown in Fig.
8 is explained.
[0131] A calibration curve varies in accordance with a concentration region in immune reaction.
Consequently, verification and confirmation with respective standard solutions are
required when calibration is carried out. For example, although the width of Min -
Max is nearly constant in respective concentration regions in a reaction system in
which a signal and a concentration are in the relationship of monotonic increase like
enzyme reaction, in antigen-antibody reaction, as shown in Fig. 9, the sensitivity
is low at a low concentration and hence the width of the concentration corresponding
to a scattered light intensity or an absorbance is very wide. At a high concentration
in contrast, it is obvious that the sensitivity is good because the width of Min/Max
is small.
[0132] Here, the allowable concentration range of each standard solution can be set by either
of the following two (a) and (b) methods, for example.
- (a) As shown in Figs. 10A and 10B, the allowable range (calibration of Max/Min) of
a calibration result is set from the double-width of Max/Min of the twice measurement
result of each standard solution.
- (b) As shown in Fig. 11, the allowable range of calibration (calibration of Max/Min)
is set as the variation of an optical system (photometer) from the uncertainty decided
beforehand to a standard solution. With regard to the uncertainty, a signal is converted
from the concentration range described in a document.
[0133] Then in the allowable concentration range obtained as stated above, the calibration
curves are compared and the concentrations are computed from the calibration of the
allowable ranges as stated below.
[0134] A calibration Abs of an absorbance is represented by Conc.
Abs, a calibration AMax by Conc.
AMax, and a calibration AMin by Conc.
AMin.
[0135] Further, a calibration I of the light-scattering photometer is represented by Conc.
I, a calibration IMax by Conc.
IMax, and a calibration IMin by Conc.
IMin and then Conc.
AMax - Conc.
AMin = (delta) Conc.
A and Conc.
Imax - Conc.
IMin = (delta)Conc.
I are computed. That is, the concentration widths of the measured concentrations of
the respective photometers are computed.
[0136] Then the computed (delta)Conc.
A and (delta)Conc.
I are compared and the one having a narrower allowable range when a concentration which
the two calibration curves can take exists in a reliable interval is adopted. For
example, in the case of (delta)Conc.
A> (delta)Conc.
I, Conc.
I is adopted as the reported value. That is, the measurement value by the light-scattering
photometer is selected.
[0137] Then the measurement result in which the dispersion of the concentration is small
(the measurement result of the light-scattering photometer in the above example) in
the measurement results of the optical system (light-scattering photometer or absorptiometer)
selected at Step S5 is reported as the final concentration. That is, the measured
final concentration, together with the optical system used for measuring the concentration,
is displayed on the CRT 25 and printed through the printer 22. Further, it is stored
in the FD 23 and the memory 11.
[0138] Here, when Conc.
I and Conc.
A do not fall within the allowable ranges of both the optical systems (the light-scattering
photometer and the absorptiometer), the sensitivity computation section 18d supplies
a signal indicating the abnormality to the CRT 25 (concentration display section)
and displays alarm showing the abnormality.
(5) Interference substance check
[0139] There is a method of checking from a data difference between the light-scattering
photometer and the absorptiometer.
[0140] That is, the computation of the reported value of a concentration is decided with
either the light-scattering photometer or the absorptiometer by a concentration computation
logic to compare sensitivities and select a photometer as described already. When
concentration dissociates between the light-scattering photometer and the absorptiometer
however, there is a possibility of causing abnormality with either of the photometers.
When data dissociate, alarm is generated with the CRT 25 and the like. In the judgment
of data dissociation, concentration percentage or concentration difference can be
selected and it is set by concentration ranges (low, middle, and high concentrations).
[0141] Whether or not dissociation occurs is judged by using the following expression (9)
in the case of the percentage judgment and by using the following expression (10)
in the case of the concentration judgment.
[0142] [Num-9]

[0143] [Num-10]

[0144] In this way, in Example 1 according to the present invention, the configuration is
devised so as to: be provided with a light-scattering photometer and an absorptiometer;
with regard to each of the analysis items, measure it simultaneously with the two
photometers of the light-scattering photometer and the absorptiometer; set an allowable
range to a calibration curve; and use the concentration of the photometer having the
smaller difference between the maximum concentration and the minimum concentration
in the allowable range.
[0145] As a result, it is possible to: compute the concentration of an identical reaction
solution by the analysis methods of an absorptiometric method and a light-scattering
photometric method having different measurement principles; and measure a reagent
of latex nephelometry at a higher sensitivity. Further, it is possible to provide
a highly-reliable measurement result to a clinical side.
[0146] That is, it is possible to: decide an optimum photometer in accordance with a concentration
range from two photometers of a light-scattering photometer and an absorptiometer;
and materialize an automatic analysis apparatus and a sample measuring method, which
can improve detection sensitivity.
Example 2
[0147] Example 2 according to the present invention is explained hereunder.
[0148] Although a concentration judgment flow to select a photometer by comparing sensitivity
is explained in Example 1 according to the present invention, Example 2 is the example
of: carrying out the operations of Steps S1, S2, S3, S8, and S9 shown in Fig. 8; and
selecting a photometer from a concentration range table.
[0149] The other configurations are the same between Example 1 and Example 2 and hence detailed
explanations are omitted.
[0150] In Fig. 8, a sample is measured at Steps S1, S2, and S3 and an interim concentration
is computed from absorbance data by using a calibration parameter at Step S8. Then
the computed concentration region is classified into three regions of low, middle,
and high and a concentration range table is developed.
[0151] Successively, at Step S9, with regard to a low concentration, a middle concentration,
and a high concentration, which combination of a concentration and a photometer used
for measuring the concentration is selected is decided from the developed concentration
range table. A concentration by scattering is selected in the low concentration region
and either of a concentration by scattering or a concentration by absorbance may be
selected in the middle concentration region. Further, a concentration by absorbance
is selected in the high concentration region.
[0152] In Example 2 according to the present invention too, it is possible to: decide an
optimum photometer in accordance with a concentration range from two photometers of
a light-scattering photometer and an absorptiometer; and materialize an automatic
analysis apparatus and a sample measuring method, which can improve detection sensitivity.
[0153] Here, the above examples are based on the case of using two photometers of a light-scattering
photometer and an absorptiometer but the present invention is applicable also to the
case of using plural photometers of other different types.
Description of Reference Numerals
[0154]
- 1
- Reaction disk
- 2
- Reaction container
- 3
- Constant-temperature bath
- 4
- Constant-temperature retaining device
- 5
- Sample disk
- 6
- Sample container
- 7
- Movable arm
- 8
- Pipet nozzle
- 9A, 9B
- Reagent cool box
- 10A, 10B
- Reagent bottle
- 11
- Memory
- 12A, 12B
- Pipet nozzle for reagent
- 13A, 13B
- Reagent dispensing mechanism
- 14A, 14B
- Light source
- 15A
- Light-scattering photometer
- 15B
- Absorptiometer
- 16
- A/D converter
- 17
- Reaction container cleaning mechanism
- 18
- Computer (controller)
- 19
- Interface
- 20
- Sample dispensing control section
- 21
- Reagent dispensing control section
- 22
- Printer
- 23
- External output medium
- 24
- Keyboard
- 25
- CRT display
- 26A, 26B
- Reagent disk
- 34A, 34B
- Bar-code reader